In general terms, the instant invention relates to agricultural baling machines for forming generally discrete cylindrical bales of crop material, commonly referred to as round bales, and more particularly to an improved twine box for holding, storing and dispensing twine that is used for wrapping the cylindrical bale to maintain its shape and structural integrity after it is formed in the bale-forming chamber and deposited on the ground.
Round balers have become quite popular throughout the world over the last twenty-five years, to the extent that they have, except for very specific-use situations and operations, all but replaced the previously universally accepted rectangular baler. Farmers have found that the advantages of a larger bale, improved storage and weathering characteristics, and reduced labor costs outweigh the increased equipment costs.
Round balers generally have a bale-forming chamber defined by a pair of opposing side walls associated with an array of side-by-side belts, transverse slats trained on chains, a plurality of transverse rolls or a combination of these various elements. During field operation, windrowed crop material such as hay is picked up from the ground and fed in a continuous stream into a fixed or variable diameter chamber. The hay is rolled into a cylindrical package within the chamber, wrapped with twine, net or plastic wrap and ejected onto the ground for subsequent handling.
U.S. Pat. No. 5,289,672, issued on Mar. 4, 1994, in the name of Kenneth R. Underhill, and U.S. Pat. No. 4,956,968, issued on Sep. 18, 1990, also in the name of Kenneth R. Underhill, disclose one type of prior art round baler of the general nature described above. In this particular type of baler, a pair of fixed sidewalls defines an expandable chamber, and a plurality of side-by-side belts cooperating with a series of transverse rolls mounted between a pair of pivotally mounted arms. This arrangement of rolls and arms is commonly referred to as a sledge assembly. The chamber includes an inlet opening in the front through which crop material is fed. Also included is a pair of take-up arms pivotally mounted on the main frame, between which arms a pair of guide rolls is journaled. A biasing force on the take-up arms urges the outer surfaces of the guide rolls against the belts to maintain tension and thereby prevent slack from occurring in the belts during expansion and contraction of the chamber. Varying the force on the take-up arms regulates the density of the bale.
Another type of prior art round baler of the same general nature as that described immediately above employs a plurality of transverse rolls to define a cylindrical bale-forming chamber having a fixed diameter. Examples of this type baler are shown in U.S. Pat. No. 4,612,855, issued on Sep. 23, 2986, in the name of Robert A. Wagstaff et at., U.S. Pat. No. 4,604,848, issued Aug. 12, 1986, in the name of Gerhard Clostermeyer, and U.S. Pat. No. 4,841,851, issued on Jun. 2, 1989, in the name of Pierre Quataert. It should be noted that the '851 patent shows additional embodiments wherein a fixed diameter chamber is defined by means other than rolls. U.S. Pat. No. 5,349,806, issued on Sep. 27, 1994, in the name of John R. Swearingen et al. and U.S. Pat. No. 4,610,123, issued Sep. 9, 1986, in the name of Bernard Krone et al. are additional examples of prior art round balers having fixed diameter chambers defined by transverse slats.
The instant invention relates to apparatus for storing twine used in a wrapping system for a round baler. The type of round baler to which the instant invention is adaptable is basically unlimited, because, as will be discussed further below, the twine box of the instant invention can prove advantageous in several ways over similar devices heretofore known and used in substantially all types of round balers.
As stated above, it is not uncommon in prior art round balers to dispense the twine from a storage container carried on the baler main frame, as shown, for example, in the '968 patent referred to above. The novel and unique characteristics of the instant invention, described in detail below, contribute to a wrapping system for round balers that conveniently stores twine in a location consistent with the appropriate introduction of twine to the periphery of the cylindrical package of crop material formed in the bale-forming chamber, regardless of whether the diameter of the chamber is fixed or variable, and regardless of the nature of the transverse wall, i.e., whether belts, rolls, slats, or a combination thereof.
U.S. Pat. No. 6,247,291, issued on Jun. 19, 2001, in the name of Kenneth R. Underhill, discloses a storage apparatus for round balers wrapping material. The term “wrapping material” encompasses not only twine, but also, rolls of wrapping material, such as net and plastic wrap. In order to be able to alternatively dispense these two types of wrapping material, the storage means, or container, is pivotably mounted to the main frame, across the front of the bale-forming chamber. This patent (U.S. Pat. No. 6,247,291) is hereby incorporated herein in its entirety by reference, as well as any documents incorporated therein by reference.
A family of presently commercially available machines, exemplified by the New Holland Model 688 Round Baler, employs a storage apparatus similar in some respects to that shown in the '291 patent; however, the storage compartment includes space only for net/plastic wrap and two balls of twine, one at each end of the net/plastic wrap roll. In order to employ more than two bales of twine, an important efficiency characteristic, the operator must remove much of the net/plastic wrap mechanism to make room for additional twine bales.
Some difficulties and shortcomings have been identified in the structure of the '291 storage means, including the inconvenience of having too little storage space, under practical conditions, for twine to maximize efficiency of the baler in field operation. Also, the process has been found to be inconvenient and excessively time consuming to switch between twine and net/plastic wrap operations. Further, the commercially available machines, such as that mentioned above, are also more difficult to change over to efficient twine operation. The unique features proffered by the structure of the instant invention overcome the shortcomings identified and contribute to improved performance and operability of round balers. Additionally, these features are consistent with simplification and enhancement of routine serviceability as well as field maintenance, all of which lead to a baler that is significantly more operator friendly than prior art balers.